Safety device for fluid fuel burners



2 Sheets-Sheet 1 Filed June 27, 1936 i Z m3 0 6 1.

9 2 Z 0 m W 601'! 6: Il a/2712i July 5, 1949. c. e. KRONMILLER SAFETY DEVICE FOR FLUID FUEL BURNERS 2 Sheets-Sheet 2 A 4 I I 0 1 Van,

Filed June 27, 1956 Patented July 5, 1949 2,475,430 SAFETY DEVICE FOR FLUID FUEL BURNERS Carl G. Kronmiller,

Minneapolis, Minn. assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application June 27, 1936, Serial No. 87,706 27 Claims. (Cl. 158-11721) My invention relates to control apparatus and more particularly to control apparatus designed for use in a fuel burner control system.

In fluid fuel burner control systems employing a constantly burning pilot for igniting the fuel supply to the main burner, it is customary to employ an arrangement generally designated as a safety pilot which is effective to prevent fuel from being supplied to the burner unless the pilot burner is lit. The safety pilot arrangement may either take the form of a valve in the main fuel line and apparatus for insuring that the valve is closed if the pilot burner is not ignited or of apparatus associated with the main shut-off valve to insure that the same will be in closed position when the pilot is extinguished. Due to the fact that the extinguishment of the pilot is often due to conditions which should be corrected before the system is again placed in operation, it is desirable in many instances to so arrange the safety pilot mechanism that it is necessary for a manual operation to be performed in addition to relightlng of the pilot in order for the system to again be placed into operation. In the case of the first type of safety pilot mechanism mentioned above which comprises a separate valve in control of the main fuel line, such mechanism commonly takes the form of some means for opening the valve and holding it open until a member responsive to the presence of a flame at the pilot burner is effective to hold it in this position when the manual would he suddenly ignited with explosive violence.

The object of the present invention is to provide in apparatus of the general type previously discussed, an arrangement wherein it is impossible to even momentarily permit fuel to be supplied to the burner through manual operation of the resetting device, if the pilot is not ignited.

A further object of the present invention is to provide in such safety pilot apparatus an arrangement whereby it is impossible to interrupt the supply of fuel to the burner by accidental operation of the resetting device when the pilot is burning.

A further object of the present invention is to provide an arrangement of this type wherein a magnet controlled by a thermo-couple responsive to the pilot flame is the means effective to hold the valve in open position.

A further object of the present invention is to provide a new and novel arrangement for actuating a holding element in a safety pilot arrangement, employing a flexible connecting member housed in the tube as a medium for imparting movement from an element responsive to the presence or absence of a flame at the pilot burner to a holding means which is eifective to hold the fuel control device in a position permitting the flow of fuel.

Other objects of the present invention will be apparent from consideration of the accompanying specification, claims and drawing, of which,

Figure 1 is a schematic view of a portion of a burner control system employing the novel controlling mechanism of the present invention;

Figure 2 is a view partly in section of the valve portion of a preferred form of the invention, with the valve in closed position;

Figure 3 is a sectional view taken along the line 38 of Figure 2 and in the direction of the arrows adiacent said drawing;

Figure 4 is a view of the valve mechanism at an intermediate stage of the resetting process:

Figure 5 is a view of a portion of the valve with the valve in open position;

Figure 6 is a view of a pilot burner and a therostatic arrangement employed therein for controlling a holding device employed with the valve;

Figure 7 is a detail view of a portion of the apparatus shown in Figure 6;

Figure 8 is a schematic view of a burner control system employing a modified form of my controlling mechanism:

Figure 9 is a view in section of the modified form of the controlling mechanism of the present invention;

Figure 10 is a detail view of a portion 01' the electromagnet employed in the structure of Figure 9.

Referring to Figure 1 of the drawing, burner which may be of any conventional type is designated by the reference numeral in. Connected to the burner ii] is a pipe H which is connected to a gas main and serves to supply fuel amuse to the burner. interposed in the fuel line H is a main control valve designated by the reference numeral i2. This valve may be of any desired type. In an automatic system this valve may, for example, be of the type driven by an electric motor, the motor of which is controlled by a room thermostat or similar device. The particular form of this valve plays no part whatsoever in the present invention.

Also interposed in the fuel line H is a valve l3 which forms a portion of the novel controlling mechanism of the present application. This valve 13 is designed to cooperate with a pilot burner which is designated by the reference numeral it to form a safety pilot arrangement. The pilot burner I4 is supplied with fuel from the line ll through a pipe it. As indicated from the previous description, the function of the device is such that when the pilot burner It is not lighted, the valve is is closed, thus cutting oi! a supply of fuel to the main burner. It will be obvious that if desired the valve l3 can be placed on the other side of the main control valve it with the connection of pipe ii to the fuel line H interposed between the two valves so that when valve i3 is closed a supply of fuel to both the main burner and the pilot burner is cut off. Inasmuch as either form can be employed, the form shown in the drawing has been selected for illustration because of its greater ease of illustration.

Referring first to Figure 2, the valve of the present invention is shown as comprising a valve body 20 having the usual inlet and outlet connections 2i and 22. The valve body 20 is also provided with the usual transverse partition wall 23, which is provided with an opening therethrough providing a valve seat 2|. A valve disc 25 which is provided with suitable valve facing material 26 is adapted to seat on thevalve seat 2|. The facing material 26 is held against the main portion of valve disc 25 by a washer 21 and a nut 28 which serves to clamp the various members of the valve disc arrangement together between the nut and a shoulder 29 on a valve stem 80. The valve body is closed at the top by a cap 32 which is secured to the valve body by a screw threaded flanged collar 33.

Secured to the interior of the valve body by screws 36 or other suitable fastening means is a U-shaped bracket 81. Plvotally supported by the bracket 31 is a bell crank lever 38. One arm of the bell crank lever 38 consists of a U-shaped portion 39, the front base leg of which is inclined as indicated at ll. One leg of the U- shaped arm 39 extends upwardly to provide the other arm ll of the bell crank lever.

Pivotally connected to the foremost portion of the arm 39 of bell crank lever 38 through a pivot pin 44 is a second bell crank lever 45. This lever consists of an arm 40 best shown in Figures 3 and 4 which consists of two side portions 41 connected by a cross-member It. A second arm 49 consists of a single member of angular shape as shown most clearly in Figures 3 and 4. The two spaced legs 41 of the arm 46 of hell crank lever 45 are provided with pins extending into slots ill in the valve stem 30.

Secured to the cap M is a rod 55 on which the valve stem 30 is slidably mounted. A spring it bears against the under side of the cap and the upper side of valve 30 and urges the valve to closed position.

Extending through the valve body is a stem BI of a manual valve operator for resetting the valve. This operator is provided at its outermost end with a knob 6| which bears against a boss projecting from the valve housing. The stem to of the operator is provided with a collar 62 and a spring 63 is interposed between the inner wall of the valve housing and the collar 62, which spring serves to bias the operator into its innermost position. Also resting against the collar 62 is the uppermost end of the arm ll of bell crank lever 38. It will be readily seen that withdrawal of the operator against the action of spring 63 will rotate the lever 38 in a counterclockwise direction.

Slidably mounted in a sleeve threaded into the valve housing, is a pin 65 which pin is biased inwardly by a spring 61 as will be more fully explained later. This pin 66 constitutes the means for holding the valve open as will be clear from a subsequent explanation of the operation of the device. Secured to the cap 32 is a leaf spring member Ill which projects into the path of movement of the arm 49 of bell crank lever 5 under certain conditions.

In order to more clearly understand the function of the apparatus to be subsequently described the operation of the portion of the apparatus which has been just described previously will now be set forth. With the elements in the position shown in Figure 2, the pin 66 does not extend into valve housing of Figure 2, being in the position assumed when the pilot is extinguished. If the knob iii of the manually operated reset mechanism is withdrawn causing collar 52 to move to the left, bell crank lever 38 will be rotated in a counter-clockwise direction bringing the lever substantially to the position shown in Figure 4. In this figure the pin 66 is shown as projecting into the path of the foremost portion ill of the arm 39 of bell crank lever 38, the position assumed when the pilot is ignited. Under these conditions the bell crank lever 40 is held against return movement. It will also be noted that rotation of the bell crank lever 38 in a counterclockwise direction has caused rotation of hell crank lever it about the pivotal connection provided by pins of legs 41 moving in slots 5i so as to bring the upwardly extending arm 49 of bell crank lever 5 into engagement with the end of stem an of the manual operator. It will be noted, however, that in spite of the fact that the manual operator Si is fully withdrawn the valve 25 remains in engagement with the valve seat 24.

Under the conditions shown in Figure 4, if the manual operator is now released the spring 63 is effective to force the stem 50 to the right rotating the bell crank lever 45 in a clockwise direction about the pivot pin 44. This action causes the arm 46 of lever 45 to raise the valve stem 30 against the biasing action of spring 58 and consequently to move the valve away from the seat. The various elements will then be in the position shown in Figure 5. It will be noted that during the movement following from the release of the knob SI of the manual operator, the upwardly extending arm 38 of bell crank lever 49 has ridden over leaf spring 10, snapping over the end thereof, so that leaf spring 10 is effective to prevent counterclockwise rotation of bell crank lever 45 about pivot pin 44.

The action Just described is that which takes place when the withdrawal ofthe knob 6| of the manual reset mechanism is made at a time when the pilot is burning and the pin 66 constituting the holding device of the valve is in the position assumed under such conditions. If, however, pin 86 is not in its foremost position when the other elements are in the position shown in Figure 4, the releasing of knob 8i merely results in bell crank lever 38 rotating in a clockwise direction back to the position shown in Figure 2, with the bell crank lever 45 pivoting about the pins in the slots 5| rather than about pin 44. It will thus be seen that under these conditions the operation of the resetting mechanism does not at any time change the position of the valve. In other words, the resetting device can be operated as often as desired without altering the relative position of the valve and valve seat. In this way the mechanism overcomes the disadvantages of the prior device wherein the operation of the reset mechanism momentarily opens the valve.

It will be further noted that with the elements in the position shown in Figure 5, the withdrawal of knob 6| will not permit the valve to move to closed position. This is due to the presence of the leaf spring 18 which, as previously explained, is effective to prevent counterclockwise rotation of hell crank lever 45. If this leaf spring 18 were not provided, withdrawal of knob El would permit bell crank lever 85 to rotate in a counterclockwise direction permitting the valve to close until the knob BI is again released. This would have the disadvantage that in the event that knob BI is accidentally pulled out while the burner is in operation, the main burner would be extinguished. pilot burner is extinguished, both burners will then be extinguished. The subsequent release of knob 5| would then permit unignited gas to be admitted to the furnace until the thermostatic element associated with the pilot burner had cooled oif sufliciently to withdraw the pin 88 to enable the valve to close. With the present arrangement, however, it is impossible to close the valve even momentarily after the same is opened so that the gas will continue to flow through the main burner and in the event of the pilot burner being extinguished, the main burner will continue to operate until the pilot burner has cooled down sufiiciently to withdraw the pin 68 and cause the immediate closing of the valve 25.

In the previous description of the apparatus it was assumed that some means was provided for moving pin 86 against the action of spring 61 whenever the pilot burner was extinguished. One such means will now be described.

Referring to Figure 6, the pilot burner II is shown as comprising a burner tube having an opening 16 adjacent the upper end thereof and an elongated slot H communicating therewith. At the lower end of the burner tube 15 an opening 19 is provided for the admission of air while extending into the lower end of the burner tube is a nozzle 80 which admits to the burner the gas flowing therethrough by pipe I5. A member 82 serves to couple pipe l5 with the burner tube 15. This member further serves as the bracket for a bell crank lever 83 which is pivoted thereto at 8|. Bell crank lever 83 comprises two arms of bimetal material 84 and 85 which are both secured to a common pivotally mounted member 86. The uppermost end of bimetallic element 84 is bent substantially horizontally at 88 and engages the burner tube 15. As best shown in Figure 7, this portion 88 is provided with an opening 88 to prevent interruption of the flame issuing from the slot 11. Member 82 is provided on the side opposite to that which lever 83 is pivoted with the large portion 88 through which extends an aperture. Extending through this aperture and secured to member If while the knob is held out, the

82 by flaring is a flexible tube 8|. This tube houses a chain 92 or other flexible member which is connected to a threaded stem 88. This stem extends through an opening in the bimetallic element and is provided with nuts 84 which abut the bimetallic element.

The device is shown in Figure 6 in the position assumed when the pilot burner is ignited. In this position, the bimetallic element 84 is bowed inwardly due to the heat of the pilot burner flame. At the same time, the bimetallic element 85 is very slightly deflected upwardly due to the heat indirectly transmitted to the same through the bimetallic element 8|. Due to the relatively greater bowing of bimetallic element 84, however, the stem 83 will be in its lowermost position, the cold position of hell crank lever 83 being indicated in dotted lines.

Due to the fact that the high expansion side of element 84 is adjacent the low expansion side of element 85 any bowing in these two elements caused by changes in ambient temperature will compensate each other so that any tendency for the outer end of bimetallic element 85 to be lowered as a result of element 84 being bowed inwardly by increase in the ambient temperature will be compensated by the outer end of element 85 moving upwardly as a result of that element being deflected upwardly as a result of being exposed to the same ambient temperature. In this manner it is assured that any movement imparted to the flexible chain 82 by reason of deflection of the bimetal element will be due to some change in temperature which affects element 84 more than element 85 and which would arise only by reason of the pilot being ignited.

Referring again to Figure 5, it will be noted that the outermost portion of pin 86 extends through a bushing 88 which is threaded into a sleeve member 85. This bushing serves to guide the path of pin 88 and at the same time serves to couple the other end of tubing 8| to the sleeve 85, As will be apparent from this figure the other end of flexible chain 82 is connected to pin 66 through a coupling member 88. It will thus be seen that at any upward movement imparted to stem 83 by reason of the pilot flame being extinguished and the thermostatic element cooling off, will cause flexible chain 82 to pull member 66 outwardly against the action of spring Bl. Withdrawal of pin 66 will permit the bell crank lever 38 to rotate in a counter-clockwise direction permitting the valve to close.

It will thus be seen that I have provided a novel arrangement for actuating the holding means of the valve mechanism in response to the absence or presence of the pilot flame. This means is moreover free from the effect of ambient temperature so that there is no danger of the safety pilot mechanism permitting the valve to be opened in the event of an extremely hot ambient temperature such as may exist in a motor room under some conditions.

In Figures 8 and 9 there is shown a modified form of the invention wherein the holding means for the valve is actuated by an electro-magnet which in turn is energized by a thermo-couple, the hot junction of which is located adjacent the pilot burner. Referring first to Figure 8, there is shown a burner control system wherein the controlling mechanism of the space is employed. A burner is designated by the reference numeral Ill) and is supplied with fuel through the pipe I l I connected to a gas supply. Interposed in the pipe III is a main controlling valve H2, which corresponds in function to the valve I2 of Figure 1. Corresponding to valve I3 of Figure 1 is valve II3 of Figure 8 which valve functions to interrupt the supply of fuel to the burner in the event the pilot burner should be extinguished. The pilot burner is designated by the reference numeral Ill and is supplied with fuel through a pipe II5. A thermocouple which energizes the electro-magnet referred to as operating the holding means is generally designated by the reference numeral H and is shown located in the flame of the pilot burner III,

In Figure 9 the structure of the valve and the actuating mechanism for the holding means is shown. In this figure as well as in Figure 8, the elements corresponding to those shown in Figure 2 are given a reference character 100 higher than the number of the corresponding element in Figures 1 to 5. Thus the valve comprises a valve body I20 having inlet and outlet connections I2I and I22. the valve body being provided with a transverse partition I23 which is connected to valve seat I24. A valve disc is designated by the reference numeral I25 and is provided with valve facing material I20 which is held in engagement with the valve disc I25 by a washer I21 and a nut I20 which serves to clamp the members against a collar I20 of a valve stem I30 in a manner similar to that described in connection with Figures 2 to 5. As in the previous species, the valve body is closed by a valve cap I32 which is held in place by a screw threaded flanged collar I03.

Secured to the valve body I20 is a U-shaped bracket I31 and pivoted to this bracket is a bell crank lever I30. Pivoted to bell crank lever I30 through a pivot pin I is a second bell crank lever I45. The structure and relation of members I01. I30 and I45 is exactly the same as that of members 31, 30 and 45 of Figure 2 so that a further detailed explanation of these members is deemed unnecessary in connection with this figure.

As in the preceding species, a. stem I55 is secured to the cap I32 of the valve housing and the stem I30 is slidably mounted on downwardly extending stem I55. A spring I50 bears against the cap I32 at its upper end and against the end of the valve stem I30 at its lower end and serves to bias valve stem I30 to a closed position.

The manually operable reset device consists of a stem I00 and a knob I6I, the stem I00 having a shoulder I02 against which bears a spring I00. All of these parts are similar to the corresponding parts of the previous species, A pin I00 extends into the valve casing into the path of the forward portion of bell crank lever I30 in a manner similar to the method in which pin I55 contacted with bell crank lever 30 in the previous species.

A leaf spring I10 is secured to the wall of the valve housing I20 through a bracket I12. This leaf spring I10 cooperates with member I in the manner similar to that which the corresponding elements of the previous species cooperated.

The structure described so far in connection with Figure 9 is substantially the same as that shown in Figures 2 to 5. As previously indicated, however, the essential difference between the previously described species and the present species is in the means for actuating the holding pin I00. As previously indicated, this pin in this species is actuated by an electro-magnet which is energized by a thermo-couple H5. The electro-magnet is housed in a casing member I15 oi' non-magnetic material, which is secured to valve casing I20 by screws I or other suitable fastening medium.

The electro-magnet referred to consists generally or a u-shaped core member I11 and a cooperating armature member I10. The core member I11 is fastened to a disc I00 which disc is in turn secured to the casing I15. The armature I10 is held in a clip I10 which is connected to a crossbar I00 through a strain release connection consisting of a pin IOI and a spring I02 interposed between the crossbar I00 and the clip I10. The crossbar I00 is connected to the two side portions I00 and IOI of a yoke member comprising said side portions I00 and IOI and the transverse bar I02. The pin I00 is connected to the transverse bar I02, A spring I00 bears at one end against the bar I02 and at the otherend against a closure plate I04 which is in turn secured to casing I20 and serves to bias the armature away from the core member I11. The two side portions I00 and IOI of the yoke extend through tubular guiding sleeves I05 and I00.

In Figure 10 the clip portion I10 is shown in somewhat greater detail. It will be noted from this figure that the crossbar I00 is provided with side members I00 which serve to guide the clip I10 and consequently the armature I10. The side flanges I00 served to prevent turning 01 the armature I10.

A thermo-oouple is generally indicated by the reference numeral H0. This thermoecouple comp-rises the usual elements 200 and 20I of difierent thermo-electric characteristics which are joined at 202 to provide the hot junction" of the thermo-couplc. While the materials employed for elements 200 and 20I may be any material having suitable thermo-couple characteristics, I have found it desirable to employ an inner member of "constantan, an alloy comprising approximately nickel and 50% copper, and an outer member 200 of stainless steel. The stainless steel employed may be any suitable stainless steel capable of adequately resisting the heat of the pilot burner flame. The inner member MI is secured to a conductor 203 which is insulated as at 204. The outer member 200 is connected to a copper reducing sleeve 205 which in turn is connected to a copper tubing 206. The copper tubing 200 is electrically connected through a sleeve 201 with the casing I15. The inner conductor 203 is connected to a conductor 200 through a coupling sleeve 2I0 which is suitably insulated i'rom sleeve 201 by insulating member 2| I. The conductor 200 forms the winding of the electro-magnet. The other end of the conductor 200 is electrically secured to the casing I15 at 2I2.

In order for the extremely small electro-motive force which is generated by the dlfl'erence in temperature between the hot junction 202 and the cold junction, to produce a sufficient holding action in the electro-magnet, it is necessary that the resistance of the circuit energized by the thermo-couple be extremely low. In order for this to be true it is necessary that conductors 204 and 200, copper tubing 200 and sleeve 201, to be of relatively large size so as to offer little resistance to the flow of current.

While the current generated by the thermocouple is sufiicient to energize the magnet suiiiciently to hold the armature I10 into engagement with core I11 against the action of spring I03, it is not suilicient to so energize the magnet as to cause armature I10 to be pulled into engagement with core I11. Consequently it is necessary that some means be provided for moving the armature I10 into engagement with the core I". A third bell crank lever 2|! is provided for this purpose. This bell crank lever consists of a horizontally extending arm 2I8 and a substantially vertically extending arm 2". The horizontally extending arm 2I8 lies in the path of movement oi pivot pin I44, while the vertically extending arm ill of bell crank lever H8 is adapted to engage a collar 2I9 secured to pin I88. It will be more or less apparent that upward movement of pin I44 will cause the bell crank lever 2I5 to move the pin I88 inwardly and to thus move armature I18 against the core I11 of the electro-magnet.

The operation of the device so far as the valve structure is concerned is substantially similar to that described in connection with Figures 2 to 5. Thus upon knob I8I being pulled to the left, with the valve in closed position, the bell crank lever I38 is rocked in a counterclockwise direction. This movement is carried sufliciently far that pin I44 is efl'ective to rock bell crank lever 2I5 so far to the right as to pull pin I88 inwardly sufficient to cause engagement of armature I18 with core I". It will be noted in this connection that in the position shown in the drawing wherein the pin I88 is in its holding position, the arm 2H is not in engagement with the collar IIS on pin I88 nor is the lever 2I8 resting in engagement with the pivot pin I44. The reason for this is that it is necessary that, it the armature is not held in engagement with core I" when so moved, the arm 2I'I of bell crank lever N8 will have moved sufficiently to the right by the time that lever I38 would have engaged the pin, to permit the spring I93 to withdraw the pin sufficiently to permit continued clockwise movement of bell crank lever I38. In other words, unless the armature I18 is held by the core I'll the action will be as follows: The bell crank lever 2I8 will not act appreciably upon pin I88 until the bell crank lever I38 has cleared the end of pin I88 whereupon further outward movement of arm I8I rotates bell crank lever 2I5 through the action of pin I 44 thereon and causes pin I88 to be moved inwardly suflicient to cause engagement of the armature and core. Upon the knob being released, by the time that bell crank lever I38 has reached a point where it would engage pin I88 if held inwardly, the pin has moved outwardly suiliciently by reason of spring I83 so that lever I38 continues to rotate in a clockwise direction. As a result, the arrangement described permits the movement of armature I18 into engagement with core Ill while at the same time keeping it out 01' the path of movement of hell crank lever I38 unless the electro-magnet is energized.

If the magnet is energized pin I88 will be held in its innermost position and any action will be exactly the same as described in connection with previous species. In other words, the bell crank lever I33 will be prevented from rotating in a clockwise direction back to its original position so that the pivot point of pivot pin I remains stationary. The action of the stem I88 against the bell crank lever I45 through spring I83 will cause the lever I48 to rotate in a clockwise direct on raising valve stem I38 against the action of biasing spring I88, thus opening the valve. Furthermore, the leaf spring I10 snaps back of the bell crank lever I45 in the same manner as leai' spring III engaged bell crank lever 45, to prevent counter-clockwise movement of hell crank lever I45 in the event of the accidental operation of the resetting mechanism. Thus, as in the previously 10 described species, it is impossible to open the valve unless the pilot flame is ignited and after the valve has been opened it is impossible to close the valve unless the pilot burner is extinguished.

It will be seen that I have provided a safety pilot arrangement wherein it is impossible by means of manual resetting means to open the main valve unless the pilot is ignited and that further it is impossible to close the valve after the same has been opened except by extinguishing the pilot. While I have described the safety pilot mechanism in connection with a valve, it is to be understood that my invention Is not to be so limited. The valve and valve seat 24 can be replaced by any other cooperatin relatively movable members which function to either directly control the operation of the main valve or in some manner to control the operation of the main valve. Furthermore the relatively movable members constituted by the valve and valve seat in the illustrated species could Just as well be the relatively movable members oi any desired controlling mechanism. It is to be understood that the species shown in the drawing and described previously are for purposes of illustration only and that my invention is to be limited only by the scope of the appended claims.

I claim as my invention:

1. In combination, a valve, means biasing said valve to a closed position, a linkage mechanism connected to said valve, holding means comprising a condition responsive device operative upon the existence of a predetermined condition to cooperate with an element of said linkage mechanism to hold said valve in open position, and actuating means for moving said element into cooperative relationship with said holding means without moving said valve from its closed position, and upon said holding means being effective for cooperating with said linkage mechanism to move said valve to open position.

2. In combination, a valve, means biasing said valve to a closed position, a linkage mechanism connected to said valve, holding means comprising a condition responsive device operative upon the existence of a predetermined condition to cooperate with an element of said linkage mechanism to hold said valve in open position, actuating means for moving said element into cooperative relationship with said holding means without moving said valve from its closed position, and upon said holding means being effective for cooperating with said linkage mechanism to move said valve to open position, and means to prevent said valve from being moved to closed position,

when in open position, by operation of said actuating means.

3. In combination, a valve, means biasing said valve to closed position, a lever pivotally connected thereto, a second lever, a fixed pivotal mounting therefor, a pivotal connection between said first and second levers at a point spaced from the pivotal connection of said first lever to said valve, holding means, means responsive to a condition whose presence is desirable prior to the opening of said valve for retaining said holding means in an operative position when said condition exists, and a reciprocable manual operator biased to one extreme position and operative when moved against its bias to substantially its other extreme position to change the angular position of said second lever and bring it into cooperative relationship with said holding means, said change in F angular position of said second lever being eii'ective to move said first lever about its pivotal connection to said valve into the path of movement of said operator, said operator being operative upon return movement thereof by said biasing means and upon return movement of said second lever being prevented by said holding means to move said first lever and through such movement to move said valve to open position.

4. In combination, a valve, means biasing said valve to closed position, a. lever pivotally connected thereto, a second lever, a fixed pivotal mounting therefor, a pivotal connection between said first and second levers at a point spaced from the pivotal connection of said first lever to said valve, holding means, an electromasnet and a thermocouple controlling the energization thereof for retaining said holdin means in an operative position, and a reciprocable manual operator biased to one extreme position and operative when moved against its bias to substantially its other extreme position to change the angular position of said second lever and bring it into cooperative relationship wih said holding means, said change in angular position of said second lever being effective to move said first lever about its pivotal connection to said valve into-the path of movement of said operator, said operator being operative upon return movement thereof by said biasing means and upon return movement of said lever being prevented by said holding means to move said first lever and through such movement to move said valve to open position.

5. In combination, a valve, means biasing said valve to closed position, a lever pivotally connected thereto, a second lever, a fixed pivotal mounting therefor, a pivotal connection between said first and second levers at a point spaced from the pivotal connection of said first lever to said valve, holding means, means including a member distortable with changes in temperatures connected to said holding means and effective to cause said holding means to assume an operative position when said member is heated above a predetermined value, and a reciprocable manual operator biased to one extreme position and operative when moved against its bias to substantially its other extreme position to change the angular position of said second lever and bring it into cooperative relationship with said holding means, said change in angular position of said second lever being efiective to move said first lever about its pivotal connection to said valve into the path of movement of said operator, said operator being operative upon return movement thereof by said biasing means and upon return movement of said second lever being prevented by said holding means to move said first lever and through such movement to move said valve to open position.

6. In a fuel burner control system, a main burner, means controlling the flow of fuel to said main burner comprising two elements movable with respect to each other and effective in a first relative position to prevent fuel being supplied to the burner and in a second position to permit fuel being supplied to the burner, a reciprocable operator movable between a first normal position and a second position, a pilot burner, holding means, and means responsive to the presence of ignition of said pilot burner to render said holding means operative, mechanism connected to said control elements and adapted to cooperate with said holding means, said operator being effective upon movement thereof from said first to said second position to move said mechanism without aflecting the relative position of said control elements into cooperative relationship with said holding means, said mechanism being operative upon said holding means being eflective as the result of the pilot burner being ignited and upon return movement of said operator to its first normal position to cause said control elements to move relative to each other to assume their second relative position wherein they permit fuel to be supplied to said main burner, said operator being ineffective to move said elements from said second relative position.

7. In a fuel burner control system, a main burner, means controlling the flow of fuel to said main burner comprising two elements movable with respect to each other and effective in a first relative position to prevent fuel being supplied to the burner and in a second position to permit fuel being supplied to the burner, a reciprocable operator movable between a first normal position and a second position, a pilot burner, electromagnetic holding means and a thermocouple having its hot Junction located adjacent said pilot burner to cause energization of said holding means when said pilot burner is ignited, mechanism connected to said control elements and adapted to cooperate with said holding means, said operator being effective upon movement thereof from said first to said second position to move said mechanism without aifecting the relative position of said control elements into cooperative relationship with said holding means, said mechanism being operative upon said holding means being effective as the result of the pilot burner being ignited and upon return movement of said operator to its first normal position to cause said control elements to move relative to each other to assume their second relative position wherein they permit fuel to be supplied to said main burner, said operator being ineffective to move said elements from said second relative position.

8. In combination, control means comprising two elements movable with respect to each other for performing a control function, means biasing said members to a first position, holding means comprising an electromagnet, a movable armature, and a thermocouple connected to said electromagnet and operative when its hot junction is heated to energize said electromagnet sufliciently to hold said armature in engagement therewith but insufiiciently to move said armature into such engagement, mechanism connected to said control means and adapted to cooperate with said holding means, reciprocable actuating means efiective when moved in one direction to move said mechanism and said armature into a position in which said armature engages said electromagnet without moving said control elements relative to each other, said mechanism being eifective upon return movement of said actuating means to move said control elements relative to each other to a second relative position if said electromagnet is sufiiciently energized to hold said armature.

9. In a fuel burner control system, a main burner, means controlling the flow of fuel to said main burner comprising two elements movable with respect to each other and effective in a first relative position to prevent fuel being supplied to the burner and in a second relative position to permit fuel being suppliedv to the burner, a reciprocable o erator movable between a first normal position and a second position, igniting means for said main burner, holding means comprising an electromagnet, a movable armature, and a thermocouple having its hot Junction arraeao located adjacent said igniting means and connected to said electromagnet, said thermocouple being eflective when its hot junction is heated to energize said electromagnet sufliciently to hold said armature in engagement therewith but insuillciently to move said armature into such engagement, mechanism connected to said control means and adapted to cooperate with said holding means, reciprocable actuating means effective when moved in one direction to move said mechanism and said armature into a position in which said armature engages said electromagnet without moving said control elements relative to each other, said mechanism being efl'ective upon return movement of said actuating means to move said control elements relative to each other to said second relative position if said electromagnet is sufliciently energized to hold said armature.

10. In a fuel burner control system, a main burner, means controllin the flow of fuel to said main burner comprising two elements movable with respect to each other and effective in a first relative position to prevent fuel being supplied to the burner and in a second position to permit fuel being supplied to the burner, a reciprocable operator movable between a first normal position and a second position, electromagnetic holding means comprising two relatively movable elements, one an armature and the other an electromagnet, a thermo-couple, means for producing a pilot flame adjacent the hot junction of said thermo-couple, said thermocouple being connected to said electromagnet so as to cause energization of said electromagnet when said pilot flame is present, means operatively connected to said control elements and adapted to cooperate with one of said two relatively movable elements of the holding means, said operator being effective upon movement thereof from said first to said second position to move said two elements of said holding means into engagemc.t without affecting the relative position of said control elements, and said means operatively connected to said control elements being operative upon said elements of said holding means being retained in engagement as a result of the existence of the pilot flame and upon return movement of said operator to its first normal position to cause said control elements to move relative to each other to assume their sec-- ond relative position wherein they permit fuel to be supplied to said main burner.

11. In combination, a main fluid fuel burner, a pilot burner, meam controlling the flow of fuel to said main burner and biased to a flow preventing position, means for holding said controlling means in a flow permitting position, said holding means including an armature and an electromagnet, a thermo-couple connected to said electromagnet and having its hot junction exposed to said pilot burner for energizing the electromagnet sufficiently to hold said armature in engagement therewith but insufllciently to move said armature into such engagement, 3, reciprocable reset member, means operative upon movement of said reset member in one direction to move said armature into engagement with said electromagnet while maintaining said controlling means in a condition preventing fuel flow to the burner, and means operative upon return movement of said reset member to its original position and upon said electromagnet retaining said armature in engagement therewith to move said 'of said apparatus 14 controlling means to said flow permitting position.

12. In combination, a fluid supply conduit, a valve for controlling the supply of fluid through said conduit, a movable armature operable to control said valve, an electromagnet for said armature, a thermo-couple connected to said electromagnet for energizing said electromagnet, means for resetting said armature with respect to said electromagnet, and means operable to shut oi! the supply of fluid through said conduit during the resetting operation.

13. In combination, a main burner, a fuel supply line for said burner, a pilot burner for said main burner, valve means in said fuel supply line for controlling the supply of fuel through said line, a movable armature operable to control said valve, an electromagnet for said armature, a thermo-couple in roximity to the pilot burner and connected to said electromagnet for energizing said electromagnet by the heat of the pilot burner, means for resetting said armature with respect to said electromagnet, and means operable to shut off the supply of fuel through said fuel supply line during the resetting operation.

14. In a device of the character described, in combination, a controlling member having an operative position and a safety position, latch means for holding said controlling member in operative position, an electromagnet, an armature for said eiectromagnet which, by movement to retracted position, releases said latch means for moveirent of said controlling member to safety position, and reset means for actuating said armauie to attracted position and in the actuation cf the armature to attracted position being operable to move said latch means to position to pick ip said controlli member for actuation thereoi o operative position.

15. In a condition control apparatus: a device to be actuated, an actuating member, means interconnecting said device and said member and including a plurality of continuously-interconnected and normally relatively-movable elements, and means responsive to a condition of said apparatus which must be maintained during the entire period of operation thereof for so limiting the relative movement of said elements that actuation of said member efiects actuation of said device only while said required condition exists.

16. In a condition control apparatus: a device to be actuated. an actuating member, means in- *erconnecting said device and said member and including a plurality of continuously-interen- Saged and normally relatively-movable driving elements, and means responsive to a condition of said apparatus which must be maintained during the entire period of operation thereof for so conditioning said elements that actuation of said member eiiects actuation of said device only while said required condition exists.

17. In a condition control apparatus: a device to be actuated, an actuating member, means interconnecting said device and said member and including a plurality of continuously-intercugaged and normally relatively-movable driving elements, and means responsive to a, condition which must be maintained during the entire period of operation thereof for so limiting the relative movement of one of said elements that actuation of said member effects actuation of said device only while said required condition exists.

18. In a condition control apparatus: a device to be actuated. an actuating member, means inarrmso terconnecting said device and said member and including a plurality of continuously-interconnected and normally relatively-movable elements, and means responsive to a condition of said apparatus which must be maintained during the entire period of operation thereof and effective in the initial actuation of said member to so condition said elements that subsequent actuation of said member eifects actuation of said device only while said required condition exists.

19. In a condition control apparatus: a device to be actuated, an actuating member; a plurality of continuously-interconnected elements interconnecting said device and said member; said elements being normally so relatively movable that actuation of said device by said member is prevented; means temporarily moved, by the initial actuation of said member. to a position wherein relative movement of said elements is limited; electromagnetic means for maintaining said last-named means in said position so that subsequent actuation of said member effects actuation of said device; and means responsive to a condition or said apparatus which must be maintained during the entire period of operation thereof for controlling the energization of said electromagnetic means.

20. In a condition control apparatus: a device to be actuated; an actuating member; a plurality of continuously-interconnected and normall relatively movable elements so interconnecting said member and said device that only when the relative movement of at least one of said elements is limited does actuation of said member effect actuation of said device; means, including a movable arm, for limiting movement of said element when said arm is in a predetermined position; means operated by initial actuation of said member, without efl'ecting actuation of said device, for moving said arm to said position; and means, responsive to a condition of said apparatus which must be maintained during the entire period of operation thereof, for maintaining said arm in said position, so that subsequent actuation of said member then eflects actuation of said device.

21. An electrically operable safety device for controlling flow of fluid fuel to a burner, comprising, a valve body having a passage therethrough, a valve for controlling the flow of fluid through said passage, resettable holding means operable to hold said valve open, said holding means including an electromagnet and an armsture, said electromagnet having a winding of low resistance so that said electromagnet is capable of being operatively energized by a thermocouple means exposed to a burner flame, means for resetting said holding means, and means operatively cooperating with said resetting means and valve for maintaining the valve closed during the resetting operation.

22. An electrically operable safety device for controlling flow of fluid fuel to a burner, comprising, a valve body having a passage therethrough, a valve for controlling the flow of fluid through said passage, resettable holding means operable to control said valve in a position in which fluid is permitted to flow through said passage, said holding means including an electromagnet and an armature, said electromagnet having a winding of low resistance so that said electromagnet is capable of being operatively energized by a thermo-couple means exposed to a burner flame, means for resetting said holding means, and means operatively cooperating with said resetting means and valve for preventing the flow of fluid through said passage during the resetting operation.

28. An electrically operable safety device for controlling flow of iuel to a burner, comprising, a control device movable between first and second positions, resettable holding means operable to hold said control device in its second position, said holding means including an electromagnet and an armature, thermo-couple means adapted to be, exposed to a burner flame for energizing said electromagnet, means for re-, setting said holding means, and means operatively cooperating with said resetting means and said control device for maintaining said control device in its first position during the resetting operation.

24. An electrically operable safety device for controlling the flow of fuel to a burner, comprising, control mechanism for effecting first and second control actions, means biasing said control mechanism to effect its first control action, resettable holding means including an armature and an electromagnet for holding said control mechanism against its bias to effect its second control action when said electromagnet is energized to hold said armature in an attracted position, said holding means releasing said control mechanism to effect its first control action upon deenergization of said electromagnet, said electromagnet having a winding of low resistance so that said electromagnet is capable of being operatively energized by a thermc-couple means exposed to a burner flame, means for resetting said holding means to its holding position after deenergization of said electromagnet, and means operable as a part of the resetting operation to prevent said control mechanism from effecting its second control action during the resetting operation.

25. An electrically operable safety device for controlling the flow of fuel to a burner, comprising, control mechanism for effecting first and second control actions, means biasing said control mechanism to eifect its first control action, resettable holding means including an armature and an electromagnet for holding said control mechanism against its bias to effect its second control action when said electromagnet is energized to hold said armature in an attracted position, said holding means releasing said control mechanism to eifect its first control action upon deenergization of said electromagnet, thermocouple means adapted to be exposed to a burner flame forenergizing the electromagnet, means for resetting said holding means to its holding position after deenergizatlon of said electromagnet, and means operable as a part of the resetting operation to prevent said control mechanism from eflecting its second control action during the resetting operation.

26. An electrically operable safety device for controlling the flow of fuel to a burner, comprising, control mechanism for effecting first and second control actions, means biasing said control mechanism to effect its first control action, resettable holding means including an armature and an electromagnet for holding said control mechanism against its bias to effect its second control action when said electromagnet is energized to hold said armature in an attracted position, said holding means releasing said control mechanism to eifect its first control action upon deenergization of said electromagnet, said electrcmagnet having a winding of low resistance so that said electromagnet is capable of being operatively energized by a theme-couple means exposed to a burner name, means [or resetting said holding means to its holding position, after deenergization of said electromagnet, means operable as a part of the resetting operation to prevent said control mechanism from eflecting its second control action during the resetting operation, and means operable after the resetting operation has been completed to prevent operation oi said control mechanism to efl'ect its first control action upon again operating said reset means.

27. An electrically operable safety device for controlling the flow of fuel to a burner, comprising, a control device movable between operative and non-operative positions, means biasing said control device to its non-operative position, resettable holding means including an armature and an electromagnet for holding said control device in its operative position against its bias when said electromagnet is energized to hold said armature in an attracted position, said holding means releasing said control device for movement to non-operative position upon deenergization of said electromagnet, said electromagnet having a winding of low resistance so that said electromagnet is capable of being operatively energized by a thermo-couple means exposed to a burner flame, means for resetting said holding means to its holding position after deenergization i8 or said electromsgnet, and means operable as a part of the resetting operation to maintain said control device in said non-operative position during the resetting operation.

- CARL G. KRONMILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'ENTS Number Name Date 682,345 Rudd Sept. 10, 1901 841,400 Holtschneider Jan. 15, 1907 1,618,169 Bhadrick July 24, 1928 1,966,735 Beckett July 17, 1934 1,975,142 Fonseca Oct. 2, 1934 2,032,045 Branche Feb. 25, 1936 2,098,383 Furlong Nov. 9, 1937 2,114,446 Hildebrecht Apr. 19, 1938 2,183,827 Thornberry Dec. 19, 1939 2,213,844 Manta Sept. 3, 1940 2,321,095 Mantz June 8, 1943 2,381,926 Ray Aug. 14, 1945 FOREIGN PATENTS Number Country Date 124,950 Austria Sept. 10, 1931 

